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dc.contributor.authorWoods, Robin A.
dc.contributor.authorSanders, Hildagarde K.
dc.contributor.authorBriquet, Michel
dc.contributor.authorFoury, Françoise
dc.contributor.authorDrysdale, Beth-Ellen
dc.contributor.authorMattoon, James R.
dc.contributor.departmentBeverly K. Fine School of the Sciencesen_US
dc.description.abstractYeast cells almost completely deficient in all cytochromes were obtained by introducing two defective nuclear genes, cyd1 and cyc4, into the same haploid strain. The action of the two mutant genes is synergistic, since either gene acting singly results in only partial cytochrome deficiency. Normal synthesis of all cytochromes can be restored in the double mutant by adding delta-aminolevulinic acid to the growth medium. The optimum concentration of delta-aminolevulinate for restoration of cytochrome synthesis is about 40 muM; when higher concentrations are used, synthesis of cytochromes is partially suppressed, particularly that of cytochrome a.a3. Growth yield of the double mutant is stimulated by ergosterol and Tween 80, a source of unsaturated fatty acid. Methionine stimulates further. None of these nutrients is required for growth when sufficient delta-aminolevulinic acid is present in the growth medium. With respect to nutritional responses, the single-gene, cytochrome-deficient mutant, ole3, behaves like the double mutant. The frequency of the p-mutation in the double mutant grown in the absence of ergosterol, Tween 80, and delta-aminolevulinic acid is at least 15%. The frequency can be reduced to less than 1% by either delta-aminolevulinic acid or Tween 80. Ergosterol alone does not decrease the p- frequency. The ole3 mutant does not exhibit increased p-frequency under similar conditions of unsaturated fatty acid deficiency.en_US
dc.format.extent8 pagesen_US
dc.genrejournal articlesen_US
dc.publisherThe Journal of Biological Chemistryen_US
dc.titleRegulation of Mitochondrial Biogenesis: Enzymatic Changes in Cytochrome-deficient Yeast Mutants Requiring Delta-Aminolevulinic Aciden_US

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